1. Field of the Invention
The present invention relates to a display device having a touch panel, and more particularly, to a display device having a touch panel which effectively intercepts noise generated from a display panel to prevent the touch panel from malfunctioning.
2. Discussion of the Related Art
Recently, a touch screen enabling information input through touch on screens of various display devices has been widely used as an information input unit of a computer system. The touch screen moves or selects display information simply by user touch using his/her fingers or a stylus, thus being easily used by anyone regardless of age or sex.
The touch screen senses touch generated on a screen of a display device or a touch position and outputs touch information, and the computer system analyzes the touch information and then performs a command. As the display device, a flat display device, such as a liquid crystal display device, a plasma display panel or an organic light emitting diode display device, is generally used.
Touch screen technology is divided into a resistive type, a capacitive type, an infrared type, an ultrasonic type or an electromagnetic type according to sensing methods. Among these types, the resistive type and the capacitive type are advantageous in terms of manufacturing costs, thus being widely used.
A resistive type touch screen recognizes touch by sensing change of voltage generated by contact between upper and lower resistance films (transparent conductive films) due to touch pressure. However, the resistive type touch screen is disadvantageous in that the touch screen or a display device is easily damaged due to touch pressure and the touch screen has low light transmittance due to scattering in an air layer between the resistance films.
A capacitive type touch screen to overcome the drawbacks of the resistive type touch screen recognizes touch by sensing change of capacitance generated by movement of a small amount of charges to a touch point when a conductor, such as a human body or a stylus, touches the touch screen. The capacitive type touch screen has high durability due to use of tempered glass, has high light transmittance and excellent touch sensing capacity, and enables multi-touch, thus attracting wide attention.
In general, a touch screen is manufactured as a panel that is attached to the upper portion of a display device, thus enabling touch input. However, the display device having the touch panel is disadvantageous in that a touch sensor in the touch panel may malfunction due to ElectroMagnetic Interference (EMI) caused by noise generated from the display device, i.e., static electricity.